Risk factors for mortality in Staphylococcus aureus bacteremia.
OBJECTIVE
To analyze risk factors for, and the role of methicillin resistance in, mortality in Staphylococcus aureus bacteremia.


METHODS
Nested case-control study.


METHODS
General teaching hospital with a high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) strains, in São Paulo, Brazil.


METHODS
136 patients over 14 years old with documented S aureus bacteremia. Those who died were compared with those who survived at least 14 days.


RESULTS
Mortality within 14 days of bacteremia was 39% (53/136). Mean age was 47 years. Hospital-acquired bacteremia represented 86% (117/136) of episodes. In 26% (35/136), infection was related to an intravascular catheter and in 13% (17/136) to the respiratory tract. Septic shock occurred in 22% (30/136) of cases. MRSA was isolated in 66% (90/136). Multivariate analysis identified three variables that were significantly and independently associated with mortality: site of entry (lung, odds ratio [OR], 17.0; unknown, OR, 12.3; others, OR, 6.6); occurrence of shock (OR, 8.9), and resistance of S aureus to methicillin (OR, 4.2).


CONCLUSIONS
Our study shows that S aureus bacteremia has a high mortality, especially when the lung is the source of infection and when shock develops; resistance to methicillin may be another risk factor for poor outcome.
Conterno
L O
LO
Infectious Diseases Division of Marilia Medical School, São Paulo, Brazil.
Wey
S B
SB
Castelo
A
A
D000368:Aged; D016470:Bacteremia / Q000382:microbiology* / Q000401:mortality*; D001938:Brazil / Q000453:epidemiology; D003428:Cross Infection / Q000401:mortality*; D005260:Female; D006746:Hospital Bed Capacity, 500 and over; D017052:Hospital Mortality; D006801:Humans; D008171:Lung Diseases / Q000382:microbiology; D008297:Male; D016106:Methicillin Resistance; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000401:mortality*